/// <devdoc>
/// Loads an image from a COM stream. This will return a bitmap, icon,
/// cursor or metafile object depending on the type of data in the stream.
/// </devdoc>
unsafe private static Cursor LoadImage(UnsafeNativeMethods.IStream stream)
{
Cursor cursor = null;
SafeNativeMethods.IPicture picture = LoadPicture(stream);
if (picture.GetPictureType() == NativeMethods.Ole.PICTYPE_ICON)
{
// black magic stolen from oleaut.
stream.Seek(2, NativeMethods.STREAM_SEEK_SET);
byte b = 0;
int numRead = stream.Read((IntPtr)(int)&b, 1);
Debug.Assert(numRead == 1, "Could read 1 byte from the stream!!!");
if (numRead == 1 && b == 2)
{
cursor = new Cursor(picture);
}
// Otherwise, it's really an Icon.
}
if (cursor != null)
{
return(cursor);
}
else
{
throw new ArgumentException(SR.GetString(SR.InvalidPictureType,
"picture",
"Cursor"), "stream");
}
}
/// <devdoc>
/// Initializes this image for the first time. This should only be called once.
/// </devdoc>
private void Initialize(SafeNativeMethods.IPicture picture)
{
if (this.picture != null)
{
throw new InvalidOperationException(SR.GetString(SR.IllegalState, GetType().Name));
}
this.picture = picture;
// SECUNDONE : Assert shouldn't be needed, however we can't put SuppressUnmanagedCode
// : on the IPicture interface, so we must do an Assert.
//
new SecurityPermission(SecurityPermissionFlag.UnmanagedCode).Assert();
try {
if (picture != null && picture.GetPictureType() == NativeMethods.Ole.PICTYPE_ICON)
{
handle = picture.GetHandle();
ownHandle = false;
}
else
{
throw new ArgumentException(SR.GetString(SR.InvalidPictureType,
"picture",
"Cursor"), "picture");
}
}
finally {
CodeAccessPermission.RevertAssert();
}
}
/// <include file='doc\COM2PictureConverter.uex' path='docs/doc[@for="Com2PictureConverter.ConvertNativeToManaged"]/*' />
/// <devdoc>
/// Converts the native value into a managed value
/// </devdoc>
public override object ConvertNativeToManaged(object nativeValue, Com2PropertyDescriptor pd)
{
if (nativeValue == null)
{
return(null);
}
Debug.Assert(nativeValue is SafeNativeMethods.IPicture, "nativevalue is not IPicture");
SafeNativeMethods.IPicture nativePicture = (SafeNativeMethods.IPicture)nativeValue;
IntPtr handle = nativePicture.GetHandle();
if (lastManaged != null && handle == lastNativeHandle)
{
return(lastManaged);
}
lastNativeHandle = handle;
//lastPalette = nativePicture.GetHPal();
if (handle != IntPtr.Zero)
{
switch (nativePicture.GetPictureType())
{
case NativeMethods.Ole.PICTYPE_ICON:
pictureType = typeof(Icon);
lastManaged = Icon.FromHandle(handle);
break;
case NativeMethods.Ole.PICTYPE_BITMAP:
pictureType = typeof(Bitmap);
lastManaged = Image.FromHbitmap(handle);
break;
default:
Debug.Fail("Unknown picture type");
break;
}
pictureRef = new WeakReference(nativePicture);
}
else
{
lastManaged = null;
pictureRef = null;
}
return(lastManaged);
}
